X-Git-Url: https://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu%2Frculfhash.h;h=008b1d49f55ae86ae4bcdf86c2ce2a8c0a1c7617;hp=9b961044c17330be4d310927b4b44dfb02d0369f;hb=7f52427be704778d53f85e17fb71629b50ada827;hpb=6887cc5e59ed0275616771957b4158b68c5d5d9a diff --git a/urcu/rculfhash.h b/urcu/rculfhash.h index 9b96104..008b1d4 100644 --- a/urcu/rculfhash.h +++ b/urcu/rculfhash.h @@ -37,12 +37,22 @@ extern "C" { * 4-bytes boundaries because the two lower bits are used as flags. */ +/* + * _cds_lfht_node: Contains the internal pointers and reverse-hash + * value required for lookup and traversal of the hash table. + */ struct _cds_lfht_node { struct cds_lfht_node *next; /* ptr | DUMMY_FLAG | REMOVED_FLAG */ unsigned long reverse_hash; } __attribute__((aligned(4))); /* + * cds_lfht_node: Contains the full key and length required to check for + * an actual match, and also contains an rcu_head structure that is used + * by RCU to track a node through a given RCU grace period. There is an + * instance of _cds_lfht_node enclosed as a field within each + * _cds_lfht_node structure. + * * struct cds_lfht_node can be embedded into a structure (as a field). * caa_container_of() can be used to get the structure from the struct * cds_lfht_node after a lookup. @@ -56,6 +66,7 @@ struct cds_lfht_node { struct rcu_head head; }; +/* cds_lfht_iter: Used to track state while traversing a hash chain. */ struct cds_lfht_iter { struct cds_lfht_node *node, *next; }; @@ -163,7 +174,8 @@ struct cds_lfht *cds_lfht_new(cds_lfht_hash_fct hash_fct, * @ht: the hash table to destroy. * @attr: (output) resize worker thread attributes, as received by cds_lfht_new. * The caller will typically want to free this pointer if dynamically - * allocated. + * allocated. The attr point can be NULL if the caller does not + * need to be informed of the value passed to cds_lfht_new(). * * Return 0 on success, negative error value on error. * Threads calling this API need to be registered RCU read-side threads. @@ -172,15 +184,19 @@ int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr); /* * cds_lfht_count_nodes - count the number of nodes in the hash table. - * + * @ht: the hash table. + * @split_count_before: Sample the node count split-counter before traversal. + * @count: Traverse the hash table, count the number of nodes observed. + * @removed: Number of logically removed nodes observed during traversal. + * @split_count_after: Sample the node count split-counter after traversal. * Call with rcu_read_lock held. * Threads calling this API need to be registered RCU read-side threads. */ void cds_lfht_count_nodes(struct cds_lfht *ht, - long *approx_before, + long *split_count_before, unsigned long *count, unsigned long *removed, - long *approx_after); + long *split_count_after); /* * cds_lfht_lookup - lookup a node by key.